I calculated overall Time in a predicate using get_time(T)
as this:
print_solution :-
**get_time(T1),**
init(State),
solve(State,Solution,EndState),
writeln('Start state:'),
writeln(State),
writeln('Solution:'),
writeln(Solution),
writeln('Final state:'),
writeln(EndState),
**get_time(T2),**
**DeltaT is T2- T1,**
**write('time: '), write(DeltaT), write(' ms.\n'), nl.**